<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * An abstract means of writing data.
 *
 * Classes implementing this interface may use a subsystem which requires less
 * memory than working with large strings of data.
 *
 * @package    Swift
 * @subpackage ByteStream
 * @author     Chris Corbyn
 */
interface Swift_InputByteStream
{
	/**
	 * Writes $bytes to the end of the stream.
	 *
	 * Writing may not happen immediately if the stream chooses to buffer.  If
	 * you want to write these bytes with immediate effect, call {@link commit()}
	 * after calling write().
	 *
	 * This method returns the sequence ID of the write (i.e. 1 for first, 2 for
	 * second, etc etc).
	 *
	 * @param string $bytes
	 *
	 * @return integer
	 *
	 * @throws Swift_IoException
	 */
	public function write($bytes);

	/**
	 * For any bytes that are currently buffered inside the stream, force them
	 * off the buffer.
	 *
	 * @throws Swift_IoException
	 */
	public function commit();

	/**
	 * Attach $is to this stream.
	 *
	 * The stream acts as an observer, receiving all data that is written.
	 * All {@link write()} and {@link flushBuffers()} operations will be mirrored.
	 *
	 * @param Swift_InputByteStream $is
	 */
	public function bind(Swift_InputByteStream $is);

	/**
	 * Remove an already bound stream.
	 *
	 * If $is is not bound, no errors will be raised.
	 * If the stream currently has any buffered data it will be written to $is
	 * before unbinding occurs.
	 *
	 * @param Swift_InputByteStream $is
	 */
	public function unbind(Swift_InputByteStream $is);

	/**
	 * Flush the contents of the stream (empty it) and set the internal pointer
	 * to the beginning.
	 *
	 * @throws Swift_IoException
	 */
	public function flushBuffers();
}
